In accordance with a rapid spread of information relevant apparatuses and communication apparatuses such as a personal computer, a video camera and a portable telephone in recent years, the development of a battery to be utilized as a power source thereof has been emphasized. The development of a high-output and high-capacity battery for an electric vehicle or a hybrid automobile has been advanced also in the technical field such as the automobile industry. A lithium battery has been presently receiving attention from the viewpoint of a high energy density among various kinds of batteries.
Organic liquid electrolyte having a flammable organic solvent as a solvent thereof is used for a presently commercialized lithium battery, so that the installation of a safety device for restraining temperature rise during a short circuit and the improvement in structure and material for preventing the short circuit are necessary therefor. On the contrary, with regard to an all solid lithium battery all-solidified by replacing the liquid electrolyte with a solid electrolyte, the flammable organic solvent is not used in the battery. Accordingly, the simplification of the safety device is promoted and thereby the battery attains excellent production cost and productivity.
On the other hand, in order to achieve higher output power and higher capacity of the battery, the all solid lithium battery having a bipolar structure is known. For example, the all solid lithium battery having a laminated bipolar structure is disclosed in Patent Documents 1 and 2. However, the problem is that the laminated bipolar structure is so narrow in a distance between electrodes that the short circuit is easily caused.
Patent Document 1: Japanese Patent Application Laid-Open No. 2000-100471
Patent Document 2: Japanese Patent Application Laid-Open No. 2004-158222
Patent Document 3: Japanese Patent Application Laid-Open No. 2007-95597
Patent Document 4: Japanese Patent Application Laid-Open No. 2000-30746
Patent Document 5: Japanese Patent No. 3,608,047
Patent Document 6: Japanese Patent Application Publication No. 2002-518816